http://hdl.handle.net/1842/3110 2013-05-20T18:29:31Z http://hdl.handle.net/1842/3117 Title: Pyrolysis for waste management: A life cycle assesment of biodegradable waste, bioenergy generation and biochar production in Glasgow and Clyde valley Authors: Ibarrola, Rodrigo Abstract: Biochar production and waste treatment by pyrolysis represent an attractive solution to decrease carbon dioxide atmospheric concentrations and to enhance the enrichment of soils by treating in a more sustainable way the biodegradable waste generated in urban or rural areas. However, its application in developed regions (such as Scotland) is still uncertain due to the consolidation of other disposal and treatment technologies in the waste market. Therefore, it is necessary to analyze this technology and compare it, from an environmental and economical point of view, with other waste treatment and disposal technologies that are currently operating in Scotland, such as landfill disposal or anaerobic digestion. 2009-01-01T00:00:00Z http://hdl.handle.net/1842/3116 Title: Biomass pyrolysis processes: performance parameters and their influence on biochar system benefits Authors: Brownsort, Peter A Abstract: This study focuses on performance of biomass pyrolysis processes for use in biochar systems. Objectives are to understand the range of control of such processes and how this affects potential benefits of pyrolysis biochar systems, in particular for climate change mitigation. Slow, intermediate and fast pyrolysis processes are reviewed. Product yield distributions change depending on feedstock composition and preparation, control of temperature and material flows. These allow some control over distribution of main products – char, liquids and gases. Typical yield ranges for pyrolysis processes are defined. Variability associated with char yield is estimated at ±5% (relative). Char yield should be considered an underlying, but minor source of variability in pyrolysis biochar systems. A model study is used to compare effects on greenhouse gas balance and electricity generating capability of slow, intermediate and fast pyrolysis processes with direct combustion; there is a trade-off between these benefits following from the different product yield distributions. High char yields allow greater net CO2 benefits but lower electrical output from slow or intermediate pyrolysis. Higher liquid and/or gas yields allow greater electrical output from fast pyrolysis but less than from direct combustion. Fast pyrolysis and direct combustion have similar net CO2 effects when retained char is low. If the objectives of pyrolysis biochar systems are for climate change mitigation then processes with higher char yields should be preferred. The model is sensitive to the reference case chosen for fossil fuel substitution and to the stability of biochar-carbon in soils – a major uncertainty in the analysis of pyrolysis biochar systems. Financial analysis shows the trend in income value for pyrolysis and combustion processes is opposite to the trend in climate change mitigation benefits. Lifecycle CO2 analysis suggests dominant factors in pyrolysis biochar systems relate to carbon sequestration in biochar and fossil fuels substitution by renewable electricity. 2009-01-01T00:00:00Z http://hdl.handle.net/1842/3115 Title: A Cost Benefit Analysis of the Application of Biochar in the Scottish Whisky Industry Authors: Messenger, Simon P Abstract: Biochar is a carbon-negative process (Mathews, 2008) with large environmental credentials which is capable of sequestering vast amounts of carbon into the soil pool. Under the Kyoto Protocol, Biochar could one day be eligible for carbon credits and, depending on the legislation in the U.K., could be eligible for Renewable Obligation Certificates. The Scottish Whisky Industry is an ideal setting for the commercial development of Biochar due to the large amounts of draff coproducts produced through the production of Whisky. The Industry also has a high potential for the development of Combined Heat and Power projects as well as additional carbon capture and algal capture technologies which could lead to large energy and financial savings. The application of Biochar in the Scottish Whisky Industry could produce up to 6,000 tonnes of Biochar per distillery and could sequester up to 12,360 tonnes of CO2 annually. A Cost Benefit Analysis of the application of Biochar in the Scottish Whisky Industry shows that the development and application of Biochar in the Scottish Whisky Industry could have a positive Net Present Value over a 15 year period with returns on investment for the largest distilleries of between £2 and £2.5million. However, a Sensitivity Analysis of 84 scenarios underlines the many levels of uncertainties associated with the project which remain. 2009-01-01T00:00:00Z http://hdl.handle.net/1842/3114 Title: The best use of biomass? Greenhouse gas lifecycle analysis of predicted pyrolysis biochar systems Authors: Hammond, James A R Abstract: Life cycle analysis is carried out for 11 predicted configurations of pyrolysis biochar systems to determine greenhouse gas balance, using an original spreadsheet model. System parameters reflect deployment in Scotland, and results demonstrate that all major crop and forestry feedstocks offer greater GHG abatement than other bioenergy technologies, regardless of system configuration. Sensitivity analysis determines the relative importance of uncertain variables in the model and optimistic to pessimistic scenarios are used for system operation. Slow pyrolysis is compared to fast pyrolysis and biomass co-firing for GHG abatement and electricity production, using various scenarios for availability of indigenous Scottish feedstocks. 2009-01-01T00:00:00Z